APL Nameplate
  • Volume/Page
  • Keyword
  • DOI
  • Citation
  • Advanced
   
 
 
 

Flickr Twitter iResearch App Facebook

BROWSE VOLUMES

Year Range: 
Search Issue | RSS Feeds RSS
Previous Issue Next Issue

29 Aug 1994

Volume 65, Issue 9, pp. 1067-1197

Page 2 of 2 Pages Previous Page | Jump to Page

Epitaxial lateral overgrowth of silicon by chemical vapor deposition on ultrathin oxide layers

Y. C. Shih, J. B. Liu, W. G. Oldham, and R. Gronsky

Appl. Phys. Lett. 65, 1142 (1994); http://dx.doi.org/10.1063/1.112122 (3 pages) | Cited 4 times

Full Text: | Download PDF

Show Abstract
Selective epitaxial growth followed by epitaxial lateral overgrowth (ELO) of silicon through windows in SiO2 in a hot‐wall low‐pressure chemical vapor deposition system has been used to fabricate silicon‐on‐insulator (SOI) structures. By careful ex situ and in situ surface cleaning and low‐temperature processing, 2.5‐μm‐thick single‐crystal silicon films have been successfully deposited over oxide layers as thin as 35 Å. Dislocation densities in these SOI films over thin oxides are higher than those found in SOI films deposited on thicker oxides. Nucleation of dislocations in the epitaxially grown film is attributed to pinhole expansion in the ultrathin oxide layers during ex situ cleaning, prebake treatment, or ELO processing. An unusual crystallographic defect with attributes of a microtwin‐stacking fault complex are also observed in the ELO film appearing over thin oxide layers. A model is proposed to explain this class of defect structure and its formation mechanism.
Show PACS
68.55.-a Thin film structure and morphology
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)

Direct evidence of carbon precipitates in GaAs and InP

A. J. Moll, E. E. Haller, J. W. Ager, and W. Walukiewicz

Appl. Phys. Lett. 65, 1145 (1994); http://dx.doi.org/10.1063/1.112123 (3 pages) | Cited 18 times

Full Text: | Download PDF

Show Abstract
Raman spectra of carbon‐doped GaAs and InP show two peaks which are characteristic of C clusters with sp2 bonding. The peaks are seen in C‐implanted GaAs and InP following either rapid thermal annealing or furnace annealing. The peaks are also seen in heavily doped epilayers following furnace annealing. Various mechanisms for C precipitation are discussed. Experimental evidence suggests that the loss of the group V component at the surface during annealing may play a role in the precipitation of C.
Show PACS
68.55.Ln Defects and impurities: doping, implantation, distribution, concentration, etc.
61.72.uj III-V and II-VI semiconductors
71.55.Eq III-V semiconductors

New formation mechanism of electric field domain due to Γ‐X sequential tunneling in GaAs/AlAs superlattices

Yaohui Zhang, Xiaoping Yang, Wei Liu, Penghua Zhang, and Desheng Jiang

Appl. Phys. Lett. 65, 1148 (1994); http://dx.doi.org/10.1063/1.112124 (3 pages) | Cited 22 times

Full Text: | Download PDF

Show Abstract
We have studied the sequential tunneling of doped weakly coupled GaAs/AlAs superlattices (SLs), whose ground state of the X valley in AlAs layers is designed to be located between the ground state (EΓ1) and the first excited state (EΓ2) of the Γ valley in GaAs wells. The experimental results demonstrate that the high electric field domain in these SLs is attributed to the Γ‐X sequential tunneling instead of the usual sequential resonant tunneling between subbands in adjacent wells. Within this kind of high field domain, electrons from the ground state in the GaAs well tunnel to the ground state of the X valley in the nearest AlAs layer, then through very rapid real‐space transfer relax from the X valley in the AlAs layer to the ground state of the Γ valley of the next GaAs well.
Show PACS
73.40.Gk Tunneling
73.21.-b Electron states and collective excitations in multilayers, quantum wells, mesoscopic, and nanoscale systems

Exciton and biexciton recombination in semiconductor nanocrystals

J. P. Zheng and H. S. Kwok

Appl. Phys. Lett. 65, 1151 (1994); http://dx.doi.org/10.1063/1.112125 (3 pages) | Cited 1 time

Full Text: | Download PDF

Show Abstract
The time‐resolved photoluminescence of semiconductor nanocrystals was obtained as a function of laser excitation intensity at a low temperature. Exciton and biexciton recombination processes were clearly identified. At laser intensities lower than 3.3×105 W/cm2, only exciton recombination with a lifetime of 4 ns was obtained. At higher laser intensities, biexciton recombination with a lifetime of 1 ns appeared. At laser intensities above 106 W/cm2, recombination of electron‐hole plasma occurred with a much shorter lifetime.
Show PACS
78.47.-p Spectroscopy of solid state dynamics
78.55.Et II-VI semiconductors
71.35.-y Excitons and related phenomena
73.21.-b Electron states and collective excitations in multilayers, quantum wells, mesoscopic, and nanoscale systems

Quantum reflection and transmission of ballistic two‐dimensional electrons by a potential barrier

X. Ying, J. P. Lu, J. J. Heremans, M. B. Santos, M. Shayegan, S. A. Lyon, M. Littman, P. Gross, and H. Rabitz

Appl. Phys. Lett. 65, 1154 (1994); http://dx.doi.org/10.1063/1.112126 (3 pages) | Cited 6 times

Full Text: | Download PDF

Show Abstract
Measurements of the reflection and transmission coefficients of ballistic two‐dimensional electrons by a potential barrier, induced via a surface gate, reveal that both coefficients vary gradually with the barrier height when it is less then the electron Fermi energy. Superimposed on the gradual variation, oscillatory structure which are consistent with interference resonances are also observed. The data imply that the potential barrier seen by the two‐dimensional electrons is sharp compared to the electron wavelength.
Show PACS
73.40.Gk Tunneling
72.20.Dp General theory, scattering mechanisms

Nanocolumns composed of GaAs‐InAs jointed whiskers and SiO2 covers

M. Yazawa, K. Haraguchi, M. Koguchi, T. Katsuyama, K. Hiruma, and H. Ohta

Appl. Phys. Lett. 65, 1157 (1994); http://dx.doi.org/10.1063/1.113010 (2 pages) | Cited 3 times

Full Text: | Download PDF

Show Abstract
A dense array of nanocolumns composed of GaAs‐InAs jointed whiskers and SiO2 covers has been fabricated on InAs substrates. The cylindrical GaAs whisker with a 20 nm diameter and 1.5 μm long is jointed on top of 0.3‐μm‐long InAs whisker by vapor‐liquid‐solid epitaxy. The nanocolumns array exhibited photoluminescence at 14 K.
Show PACS
68.55.-a Thin film structure and morphology
81.07.-b Nanoscale materials and structures: fabrication and characterization
81.16.-c Methods of micro- and nanofabrication and processing
85.35.-p Nanoelectronic devices
78.55.Cr III-V semiconductors

Synthesis of dislocation free Siy(SnxC1−x)1−y alloys by molecular beam deposition and solid phase epitaxy

Gang He, Mark D. Savellano, and Harry A. Atwater

Appl. Phys. Lett. 65, 1159 (1994); http://dx.doi.org/10.1063/1.112127 (3 pages) | Cited 9 times

Full Text: | Download PDF

Show Abstract
Synthesis of strain‐compensated single‐crystal Siy(SnxC1−x)1−y alloy films on Si (100) substrates has been achieved with compositions of Sn and C greatly exceeding their normal equilibrium solubility in Si. Amorphous SiSnC alloys were deposited by molecular beam deposition from solid sources followed by thermal annealing. In situ monitoring of crystallization was done using time‐resolved reflectivity. Solid phase epitaxy for Si0.98Sn0.01C0.01 occurs at a rate about 20 times slower than that of pure Si. Compositional and structural analysis done using Rutherford backscattering, electron microprobe, ion channeling, x‐ray diffraction, and transmission electron microscopy are consistent with substitutional C and Sn, and with defect‐free single crystal films.
Show PACS
68.55.-a Thin film structure and morphology

Elastic misfit stress relaxation in highly strained InGaAs/GaAs structures

Y. Androussi, A. Lefebvre, B. Courboulès, N. Grandjean, J. Massies, T. Bouhacina, and J. P. Aimé

Appl. Phys. Lett. 65, 1162 (1994); http://dx.doi.org/10.1063/1.112128 (3 pages) | Cited 16 times

Full Text: | Download PDF

Show Abstract
The strain contrasts associated with three‐dimensional coherently strained islands formed during the epitaxial growth of highly strained In0.45Ga0.55As layers on GaAs (001) have been studied by transmission electron microscopy. It is demonstrated that the comparison of these experimental strain contrasts with simulated profiles makes it possible to assess the elastic relaxation of the islands.
Show PACS
68.55.-a Thin film structure and morphology
68.37.Hk Scanning electron microscopy (SEM) (including EBIC)
68.37.Lp Transmission electron microscopy (TEM)

Damage induced by exposing AlGaAs layers to electron cyclotron resonance SF6/CHF3 plasma

Katsuhiko Mitani, Hiroto Oda, and Yoshinori Imamura

Appl. Phys. Lett. 65, 1165 (1994); http://dx.doi.org/10.1063/1.112133 (3 pages) | Cited 2 times

Full Text: | Download PDF

Show Abstract
We investigated the damage induced by exposing AlxGa1−xAs (x=0.30, 0.15) and GaAs layers to electron cyclotron resonance SF6/CHF3 plasma and the repair of this damage by annealing. After plasma exposure the sheet resistance of all these samples is higher because of carrier reduction near the surface. This kind of damage in AlxGa1−xAs (x=0.15) and GaAs can be restored by annealing at 450 °C for 30 min. The plasma‐damaged AlxGa1−xAs (x=0.30), however, has a further increased sheet resistance after annealing, and the sheet resistance AlxGa1−xAs (x=0.3), not exposed to the plasma is unaffected by annealing. Capacitance‐voltage measurements show that annealing causes the carrier reduction in plasma‐exposed AlxGa1−xAs (x=0.30), to extend to a greater depth.
Show PACS
81.65.-b Surface treatments
61.80.Jh Ion radiation effects
73.25.+i Surface conductivity and carrier phenomena
73.61.Ey III-V semiconductors

Atomic structure and luminescence excitation of GaAs/(AlAs)n(GaAs)m quantum wires with the scanning tunneling microscope

M. Pfister, M. B. Johnson, S. F. Alvarado, H. W. M. Salemink, U. Marti, D. Martin, F. Morier‐Genoud, and F. K. Reinhart

Appl. Phys. Lett. 65, 1168 (1994); http://dx.doi.org/10.1063/1.112978 (3 pages) | Cited 23 times

Full Text: | Download PDF

Show Abstract
We report on the imaging of a molecular beam epitaxially grown GaAs/(AlAs)n(GaAs)m quantum well‐wire array by means of cross‐sectional scanning tunneling microscopy (XSTM) and scanning tunneling‐induced luminescence (STL). XSTM provides atomically resolved cross‐sectional images of sets of quantum well wires with chemical sensitivity within the group III species and electrical sensitivity to single dopant atoms. This permits the precise observation of growth mechanisms and the identification of defects responsible for inhomogeneities in the growth morphology, as well as the determination of dopant incorporation throughout the structure. STL permits the relative quantum efficiency of individual quantum wires to be quantified.
Show PACS
68.65.-k Low-dimensional, mesoscopic, nanoscale and other related systems: structure and nonelectronic properties
68.55.-a Thin film structure and morphology
68.37.Ef Scanning tunneling microscopy (including chemistry induced with STM)
68.37.Ps Atomic force microscopy (AFM)
68.37.Rt Magnetic force microscopy (MFM)
68.37.Uv Near-field scanning microscopy and spectroscopy

Electrical properties of heavily Si‐doped (311)A GaAs grown by molecular beam epitaxy

K. Agawa, K. Hirakawa, N. Sakamoto, Y. Hashimoto, and T. Ikoma

Appl. Phys. Lett. 65, 1171 (1994); http://dx.doi.org/10.1063/1.112136 (3 pages) | Cited 10 times

Full Text: | Download PDF

Show Abstract
We have systematically studied the electrical properties of heavily Si‐doped GaAs grown on the (311)A GaAs surfaces by molecular beam epitaxy. It is found that the conduction type drastically changes from p type to n type with decreasing growth temperature at a critical temperature of ∼430 °C for uniform doping and ∼480 °C for the δ‐doping case, with the transition temperature width as narrow as ∼50 °C for both cases. The highest hole density obtained for uniformly doped layers was 1.5×1020 cm−3, while for δ‐doped layers a sheet hole density as high as 2.6×1013 cm−2 was achieved, which is the highest sheet hole density ever reported for δ‐doped p‐type GaAs.
Show PACS
68.55.Ln Defects and impurities: doping, implantation, distribution, concentration, etc.
81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy
73.61.Ey III-V semiconductors

Secondary ion mass spectroscopy study of Zn or Cd implanted and rapid thermally annealed Pd/Ge contacts to p‐In0.53Ga0.47As

P. Ressel, H. Strusny, M. Trapp, H. Kräutle, and D. Fritzsche

Appl. Phys. Lett. 65, 1174 (1994); http://dx.doi.org/10.1063/1.112137 (3 pages) | Cited 4 times

Full Text: | Download PDF

Show Abstract
Backside secondary ion mass spectroscopy is used to examine elemental redistribution in Zn or Cd implanted Pd/Ge contacts to p‐InGaAs. A quaternary Pd‐In‐Ga‐As layer is observed at annealing temperatures of 200–250 °C. At temperatures ≳250 °C, this layer disappears due to PdGe formation and InGaAs regrowth. Excess Ge diffuses to the contact interface. Cd and Zn accumulate inside the regrown InGaAs creating a thin, highly doped layer. Due to its abrupt interface and the formation of a highly doped layer beneath the contact, this implanted Pd/Ge contact scheme is a promising candidate for shallow ohmic contacts to p‐InGaAs.
Show PACS
66.30.J- Diffusion of impurities
68.35.Fx Diffusion; interface formation
68.55.Ln Defects and impurities: doping, implantation, distribution, concentration, etc.
73.40.Ns Metal-nonmetal contacts

Improved step edges on LaAlO3 substrates by using amorphous carbon etch masks

H. R. Yi, Z. G. Ivanov, D. Winkler, Y. M. Zhang, H. Olin, P. Larsson, and T. Claeson

Appl. Phys. Lett. 65, 1177 (1994); http://dx.doi.org/10.1063/1.112138 (3 pages) | Cited 26 times

Full Text: | Download PDF

Show Abstract
We report a technique for the fabrication of sharp and straight step edges on LaAlO3 (LAO) substrates by ion milling. An electron beam lithography defined amorphous carbon film was used as an etch mask. It had very low ion milling rate and was easily prepared and removed. Atomic force microscopy was used to determine the step profile. YBa2Cu3O7 step edge junctions fabricated at the LAO steps show promising results. An IcRn product of 1 mV was obtained at 30 K. A Fraunhofer‐like magnetic field dependence of Ic was obtained up to ±2 Φ0. One weak link or possibly identical weak links in series for these step edge junctions were observed from the current‐voltage (I‐V) curves as well as from the magnetic field dependence of the I‐V curves.
Show PACS
85.25.Cp Josephson devices
81.65.-b Surface treatments
74.78.-w Superconducting films and low-dimensional structures

Granularity and superconductor‐insulator transition in electrochemically anodized Al films

Wenhao Wu, P. W. Adams, R. L. McCarley, and D. J. Dunaway

Appl. Phys. Lett. 65, 1180 (1994); http://dx.doi.org/10.1063/1.112139 (3 pages) | Cited 3 times

Full Text: | Download PDF

Show Abstract
We report the use of an electrochemical anodization process to fabricate ultrathin granular Al films at room temperature. These films display a superconductor‐insulator transition of the same character as those found in quench‐condensed granular films. The granularity of the films and the unusually narrow distribution of the grain sizes are shown by scanning force microscopy.
Show PACS
74.78.-w Superconducting films and low-dimensional structures
74.81.Bd Granular, melt-textured, amorphous, and composite superconductors
68.55.-a Thin film structure and morphology

Improved exchange coupling between ferromagnetic Ni‐Fe and antiferromagnetic Ni‐Mn‐based films

Tsann Lin, Daniele Mauri, Norbert Staud, Cherngye Hwang, J. Kent Howard, and Grace L. Gorman

Appl. Phys. Lett. 65, 1183 (1994); http://dx.doi.org/10.1063/1.112140 (3 pages) | Cited 96 times

Full Text: | Download PDF

Show Abstract
Dc magnetron sputtered Ni‐Mn and Ni‐Mn‐Cr films are demonstrated to exhibit strong and thermally stable antiferromagnetism, as well as high corrosion resistance. For a 25.2 nm thick 53.3 Ni‐46.7 Mn (in atomic percent) film deposited on top of a 28.5 nm thick 81 Ni‐19 Fe film, a unidirectional anisotropy field (HUA) of 120.6 Oe is obtained at room temperature after annealing in vacuum. The equivalent interfacial exchange coupling energy (JK) is 0.27 erg/cm2, three times higher than that of bilayer Ni‐Fe/50Fe‐50Mn films. This strong exchange coupling appears correlated with the presence of an antiferromagnetic θ (NiMn) phase with a CuAu‐I‐type ordered face‐centered‐tetragonal structure. The blocking temperature, at which the exchange coupling disappears, is higher than 400 °C. The Cr addition to the Ni‐Mn film dilutes the exchange coupling, but the JK for the Cr content ≤10.7 at. %, is still higher than that of the Ni‐Fe/Fe‐Mn films. Both Ni‐Mn and Ni‐Mn‐Cr films exhibit corrosion behaviors much better than the Fe‐Mn film and comparable to the Ni‐Fe film. The films are proposed as longitudinal bias layers for the stabilization of magnetoresistive read sensors.
Show PACS
75.70.-i Magnetic properties of thin films, surfaces, and interfaces
75.50.Cc Other ferromagnetic metals and alloys
75.30.Gw Magnetic anisotropy

Chemical segregation in CoNiPt(SiO2) alloy film

Akihiro Murayama, Masao Miyamura, and Shinji Kondoh

Appl. Phys. Lett. 65, 1186 (1994); http://dx.doi.org/10.1063/1.113009 (3 pages) | Cited 7 times

Full Text: | Download PDF

Show Abstract
Chemical segregation in SiO2‐added CoNiPt alloy films for high‐density longitudinal recording media have been studied by high‐resolution transmission‐electron microscopy‐energy dispersive spectroscopy with a spatial resolution of 20 Å. Sputtered CoNiPt(SiO2) films consist of well‐separated grains with diameters less than 200 Å. Si is clearly detected only in a grain boundary region with the width from 12 to 30 Å. Oxygen concentration in the grain boundary is also much higher than that inside the grain. X‐ray photoelectron spectroscopy shows that Si atoms in the film are in the form of SiO2. Therefore, it is concluded that SiO2 is segregated to the grain boundary in the CoInPt films. The development of the grain separation due to this chemical segregation explains the excellent magnetic and recording properties of the CoInPt(SiO2) films, such as high coercivity beyond 2400 Oe and low media noise. Inhomogeneity of CoNiPt alloy elements are also discussed.
Show PACS
75.70.-i Magnetic properties of thin films, surfaces, and interfaces
75.50.Cc Other ferromagnetic metals and alloys

Magneto‐impedance effect in amorphous wires

L. V. Panina and K. Mohri

Appl. Phys. Lett. 65, 1189 (1994); http://dx.doi.org/10.1063/1.112104 (3 pages) | Cited 258 times

Full Text: | Download PDF

Show Abstract
Recent experiments have discovered a giant magneto‐impedance (MI) effect in FeCoSiB amorphous wires. This effect includes a sensitive change (as much as 60%) in a high frequency wire voltage by an applied dc magnetic field and is thus a high frequency analog of giant magnetoresistance. We consider this phenomenon in terms of ac complex resistance or impedance. The giant MI effect is demonstrated to arise from a combination of a skin effect and a strong field dependence of the circumferential magnetic permeability associated with circular domain wall movements. The theoretical results agree satisfactorily with the existing experimental data.
Show PACS
75.50.Kj Amorphous and quasicrystalline magnetic materials
75.60.Ch Domain walls and domain structure
72.15.Gd Galvanomagnetic and other magnetotransport effects
72.30.+q High-frequency effects; plasma effects

Correlation between nucleation site density and residual diamond dust density in diamond film deposition

Manabu Ihara, Hiroshi Komiyama, and Tatsuya Okubo

Appl. Phys. Lett. 65, 1192 (1994); http://dx.doi.org/10.1063/1.112105 (3 pages) | Cited 20 times

Full Text: | Download PDF

Show Abstract
Diamond was deposited on substrates pre‐etched with diamond powder using either a microwave plasma chemical vapor deposition method or a hot‐filament‐assisted chemical vapor deposition method. Density of residual diamond dust (i.e., number of diamond particles per unit area on the surface of a substrate) on the pre‐etched substrates was determined using field emission scanning electron microscopy, and ranged from 3.3×107 to 6.6×1010 ♯/cm2. The diamond nucleation‐site density (i.e., number of nucleation sites per unit area on the surface of a substrate) ranged from 1.5×106 sites/cm2, typical of the deposition on a substrate etched with diamond paste, to 1.1×1010 sites/cm2, sufficient to create nanostructured diamond films. We found that the nucleation site density was about 10% of the residual dust density. Our results also show that the residual diamond dust is the main source of nucleation sites for diamond growth on diamond‐etched substrates.
Show PACS
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)
68.55.-a Thin film structure and morphology
81.10.Aj Theory and models of crystal growth; physics and chemistry of crystal growth, crystal morphology, and orientation

Adhesion force imaging in air and liquid by adhesion mode atomic force microscopy

Kees O. van der Werf, Constant A. J. Putman, Bart G. de Grooth, and Jan Greve

Appl. Phys. Lett. 65, 1195 (1994); http://dx.doi.org/10.1063/1.112106 (3 pages) | Cited 78 times

Full Text: | Download PDF

Show Abstract
A new imaging mode for the atomic force microscope (AFM), yielding images mapping the adhesion force between tip and sample, is introduced. The adhesion mode AFM takes a force curve at each pixel by ramping a piezoactuator, moving the silicon‐nitride tip up and down towards the sample. During the retrace the tip leaves the sample with an adhesion dip showing up in the force curve. Adhesion force images mapping parameters describing this adhesion dip, such as peak value, width, and area, are acquired on‐line together with the sample topography. Imaging in air gives information on the differences in hydrophobicity of sample features. While imaging a mercaptopentadecane‐gold layer on glass in demineralized water, the adhesion force could be modulated by adding phosphate buffered saline.
Show PACS
68.37.Ef Scanning tunneling microscopy (including chemistry induced with STM)
68.37.Ps Atomic force microscopy (AFM)
68.37.Rt Magnetic force microscopy (MFM)
68.37.Uv Near-field scanning microscopy and spectroscopy
68.35.-p Solid surfaces and solid-solid interfaces: structure and energetics
Page 2 of 2 Pages Previous Page | Jump to Page
Close

Google Calendar

ADVERTISEMENT

Go to AIP Home   © AIP Publishing LLC
close